The molecular biology laboratory will provide complete genetic characterization of all patients. It will enumerate HgbS genes and alpha globin genes and determine the haplotypes of the beta globin gene cluster. These data will be used to define, in one study, the correlation with clinical severity and in others, the effect on rheological characterizations both in vivo and in vitro. The core laboratory will provide rapid and precise prenatal diagnoses to parents at risk, whether both parental phenotypes are known or only the maternal one is known. We will explore new techniques of molecular biology that may improve the efficacy of the prenatal diagnosis. In addition, the core laboratory will perform a variety of hematological tests, required for the clinical care and for the more complete characterization of the patients.